pityriasis

pityriasis /pit·y·ri·a·sis/ (pit″ĭ-ri´ah-sis) any of various skin diseases characterized by the formation of fine, branny scales.

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pityriasis al´ba  a chronic condition with patchy scaling and hypopigmentation of the skin of the face.

pityriasis ro´sea  a dermatosis marked by scaling, pink, oval macules arranged with the long axes parallel to the cleavage lines of the skin.

pityriasis ru´bra pila´ris  a chronic inflammatory skin disease marked by pink scaling macules and horny follicular papules, beginning usually with seborrhea of the scalp and face, with keratoderma of palms and soles.

pityriasis versi´color  tinea versicolor.

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pit·y·ri·a·sis (pt-r-ss)

n. pl. pit·y·ri·a·ses (-sz)

Any of various skin diseases of humans and animals, characterized by epidermal shedding of flaky scales.

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pity·ria·sic (-sk) adj.

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pityriasis

[pitərī′əsis]

Etymology: Gk, pityron, bran

any of a number of skin diseases that have in common lesions that resemble dandrufflike scales without obvious signs of inflammation.

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pityriasis

a group of skin diseases in humans characterized by branlike scales on the skin surface. The skin is not thickened and its surface is unbroken. Pityriasis rosea of pigs is the only diseases in animals that is similar.

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pityriasis rosea

a disease of pigs, most commonly white breeds such as Landrace, up to 3 months old characterized by circular lesions 1 inch (2-3 cm) diameter which often coalesce to produce large irregular lesions. The central area of the lesion is an area of comparatively normal skin, covered by thin brown scales and surrounded by a very narrow, 1 to 2 mm raised zone of erythema. There is no irritation or no bristle loss and spontaneous recovery is usual. The etiology is unknown. Called also porcine juvenile pustular psoriasiform dermatitis, pseudoringworm.